Section-connecting switch



Patented Aug. 27, 1929.

UNITED STATES PATENT OFFICE.

GUSTAV E. JANSSON, OF VIOLLASTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELEC- TRICAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A

CORPORATION OF MASSACHUSETTS.

SECTION-CONNECTING SWITCH.

Application filed February 10, 1928.

This invention relates to electric switches which are adapted to connect together two sections of a high tension alternating current line, each section being energized by a separate source of alternating current power, when the two sections are in synchronism with each other.

In connecting together two separately energized high tension line-sections, it is usual practice to interpose a section-connecting switch between the sections and to connect voltage-reducing apparatus separately to the sections on opposite sides of the switch and to a low-tension synchronism-responsive or indicating apparatus, to indicate the synchronous condition Orthe sections, so

that the switch can be closed without shock to the switch or to the line, at such time.

In the patent to Wolcott, No. 1,091,722, dated March 31, 191%, apparatus for connecting the sections of the line when they are in synchronism is shown, the apparatus consisting of a switch of usual construction connected bet-ween the two sections, a sus pension-type insulator, comprising a string of insulator-elements, for supporting each line-section before its connection with the switch, and an electrostatic synchronism indicator connected between intermediate points of the insulatorstrings, the insulators thus comprising electro-static potential transformers.

This arrangement, in addition to the switch, necessitates the high-tension insulator strings, which must be remote from the switch, as out-doors when the switch is in-doors and the running of the lowtension synchronism-conductor from the dangerous vicinity of the high tension linesections to the synchronism-indicator. The installation of such a system, and the various pieces of apparatus thereof, obviously requires especial care and planning.

It is an object of the present invention to provide a section-connecting switch which has, in itself, and as an integral and vital part thereof, reduced-voltage apparatus and terminals associated with both sections to be connected through the switch, which lowvoltage terminals are adapted to be connected with a synchronismresponsive or indicating apparatus to make known the syn- Serial No. 253,446.

chronous condition of the sections, so that the switch can be closed at such time.

Since the switch, in itself, provides the re duced voltages proportional to the high voltage of each of the line-sections connected to the switch, or the switch and the voltagereducing apparatus of both sections is one and the same apparatus, the necessity for separate voltage-reducing apparatus is eliminated, the cost of the apparatus of the system, and the cost of installing the system, is greatly reduced, the synchronism-responsive or indicating apparatus can be connected with the line-sections at the section-connect- 1ng switch, which is greatly to be desired, the conductors connected with the synchronous-indicat0r are safe from accidentallyapplied high potentials, and a low-voltage electro-magnetic type or synchronism-indicater can be utilized.

A further object is to improve switches used for connecting together synchronized higlrtension lines.

Fig. 1 is a view of a pair of separatelyenergized high-tension alternating current line-sections and a switch embodying the present invention for connecting the sections when the sections are in synchronism.

Fig. 2 is a sectional elevation through one of the similar insulated high tension terminals of the switch.

As here shown the alternating-current, high-tension line consists of two sections 10 and 12, independently energized by sources of alternating current energy 14; and 16, here shown as turbo-generators. The line-sections are adapted to be connected together when they are in synchronism with each other by means or a switch 18. Said switch comprises an oil-containing enclosing casing 20 having two insulated terminals 22 and 24 which extend into the casing and are adapted to be bridged, or connected, therein by the movable switch or bridging member 26. The line-section 10 is connected with the switch terminal 22 and the line-section 12 is connected with the switch terminal 24. Each switch terminal is thus subjected to the alternating potential of a separate one of the line-sections.

The switch, in accordance with this invention, is caused to supply two reduced potentials, each one of which is derived from and is proportional to the potential of a separate one of the line-sections and, speclfically, of the switch terminals; and the switch has two low-potential terminals 28 and 30, and a third terminal 32, the latter being electrically connected with the switch casing, to which the synchronism-indicator 34 is adapted to be connected.

The reduced potential is supplied by the construction of the insulated terminals. Both terminals are, or can be, identical and each can be constructed as illustrated in Fig. As shown in this figure, the insulated terminal 22 extends through an oil-containing insulating bushing which has the outer shell 36 of porcelain and an attaching flange or collar 38 by which the bushing is secured to the top of the switch casing. Spaced concentric porcelain tubes 40 are located within the shell and about the terminal 22. An insulated metal tube, comprising a condenser plate 42 is located within the shell, between the collar and terminal, and insulated from both, and is connected with the insulated low tension terminal 28. Said plate comprises one plate of a condenser, of which the terminal 22 comprises the other plate, the oil and porcelain tubes bet-ween the plates constituting the dielectric of the condenser. The potential assumed by the plate 42, and the low-tensionterminal 28, depends upon the distance between said plate and the stud-terminal 22, and the specific inductive capacity of the dielectric between them and can be made any suitable value, less than the switchterminal potential, by a suitable choice of dimensions and material. The insulated switch terminal here shown and as above described is described and claimed ininy co-pending application Serial No. 248,237, filed January 20,1928.

The synchronism-indicator can be of any suitable type, preferably of the electro-magnetic type, not necessary to be described. It is connected by conductors 4e and 46 to the two low tension terminals 28 and 30 respectively, and thus is influenced, through the insulated switch terminals, by the potentials of both line sections, and the frequency of the sections and, by its indication, will show when the switch can be closed without shock either to the switch or to the line.

The switch thus arranged constitutes, in itself, a step-down potential transformer for the synchronism-indicator, without the employment of detached additional apparatus heretofore considered essential for connecting together line sections when they are synchronized.

I claim:

1. Apparatus for connecting together two separately-energized sections of a high-tension alternating current line when they are in synchronism, consisting of a switch for connecting the sections having two terminals each connected with a separate one of said line-sections, a low-potential terminal associated with each switch terminal and deriving potential therefrom, and a synchronism-responsive device connected with both of said low-potential terminals to indicate when the sect-ions are in synchronism and the switch can be closed.

2. An electric switch for connecting together two high tension line-sections when they are in synchronism with each other, said switch having two insulated switch terminals each connected with a. separate one of the line sections, both insulated terminals constituting electrostatic potential transformers and both having reduced-potential terminals for connection with synchronism indicating apparatus, the potentials of which terminals vary in accordance with the potentials of the insulated terminals.

3. An electric switch for connecting together two high tension line-sections when they are in synchronism with each other, said switch having two insulated stationary terminals each adapted for connection with a separate one 01' the twoline sections, and a movable switch member for connecting said terminals, each of said stationary terminals constituting a condenser having an insulated low-potential terminal, both of said low-potential terminals adapted for connection with synchronism-responsive apparatus.

4. An electric switch for connecting together two high tension line-sections when they are in synchronism with each other, said switch having section terminals, and a movable member for bridging said terminals, and also having low-potential terminals, the potential of each of which is a function of the potential of a separate one of the section terminals.

In testimony whereof, I have signed my name to this specification.

GUSTAV E. J ANSSON 

